Question: Simplify the following expression: $k = \dfrac{15r + 20t}{10r + 5} + \dfrac{5s + 5t}{10r + 5}$ You can assume $r,s,t \neq 0$.
Explanation: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{15r + 20t + 5s + 5t}{10r + 5}$ $k = \dfrac{15r + 25t + 5s}{10r + 5}$ The numerator and denominator have a common factor of $5$, so we can simplify $k = \dfrac{3r + 5t + s}{2r + 1}$